Unburned color pencil lead

ABSTRACT

For the improvement of moldability of a lead and bending strength of a lead, a non-calcined lead of a colored pencil contains a colorant, a binder, a body filler, waxes and/or oils, and a hydrophilic surfactant, and as a hydrophilic surfactant, a polyethylene additive of oils is contained. For the improvement of water resistance, a non-calcined lead of a colored pencil contains a colorant, a binder, a body filler, waxes and/or oils, and a hydrophilic surfactant, and further, a water repellent substance. Further, as a non-calcined lead of a colored pencil with easy quality control process, it contains plate type alumina and/or plate type alumina hydrate.

FIELD OF THE INVENTION

The present invention relates to a non-calcined lead of a coloredpencil. In more detail, the present invention relates to a non-calcinedlead of a colored pencil which has improved bending strength of a leadin particular, as well as having improved moldability and a tintingstrength of a lead at the time of writing. In particular, the presentinvention relates to a non-calcined lead of a colored pencil which canbe erased its written mark with an eraser. In addition, the presentinvention relates to a non-calcined lead of a colored pencil which hasimproved water resistance, with easy quality control operations, andmaintains excellent safety since it no longer contains asbestos as inconventional talc.

DESCRIPTION OF THE PRIOR ART

A conventional non-calcined lead of a colored pencil contains awater-soluble resin which is a binder, and waxes and/or oils at the sametime. Therefore, a problem of bad moldability occurs since awater-soluble resin which is a binder, and waxes and/or oils are hard tobe mixed uniformly when mixed. In addition, since waxes and/or oilsinhibit the binding force of a water soluble resin during the process ofmolding a lead, another problem of low bending strength occurs when usedas a lead of a colored pencil. In particular, in order to obtain acolored pencil which can be erased its written mark with an eraser,since it is necessary to use oily substances in liquids at an ordinarytemperature as waxes and/or oils, these problems occur more remarkablycompared with when solids at an ordinary temperature are used.

Regarding bending strength, conventionally, a non-calcined lead of acolored pencil mixing a sorbitan fatty acid ester surfactant has beenproposed in order to increase tinting amount without lowering bendingstrength of a lead (Patent Unexamined Publication SHO 51-153023).Further, a non-calcined lead of a colored pencil mixing a surfactantincluding sorbitan fatty acid ester and polyoxyethylene sorbitan fattyacid ester has been proposed in order to improve moldability and bendingstrength of a lead (Patent Unexamined Publication 2000-7976).

However, when oily substances in liquids at an ordinary temperature aswaxes and/or oils are mixed in a non-calcined lead of a colored pencilto make a written mark erasable with an eraser, the improvement ofmoldabilty and bending strength of a lead is not always satisfactorywith these surfactants.

Further, a non-calcined lead of a colored pencil which contains suchsurfactants as a hydrophilic surfactant does not always have a writtenmark with satisfactory water resistance since lowering ofstrength(moisture resistance) of a lead and lowering of water resistanceof a written mark are observed under high moisture by containing ahydrophilic surfactant. Therefore, in many cases, a non-calcined lead ofa colored pencil which contains a hydrophilic surfactant is not suitablefor the purpose which requires water resistance.

On the other hand, in a non-calcined lead of a colored pencil, variouskinds of body fillers are used depending on their properties. Inparticular, a non-calcined lead of a colored pencil which contains talcas a body filler can improve bending strength since crystals of scalytalc are oriented in one direction, and further, a non-calcined lead ofa colored pencil which contains talc is capable of obtaining a propertyas a non-calcined lead of a colored pencil having good writingperformance due to easiness of wearing and of lubricity, which arecaused by talc.

In producing a non-calcined lead of a colored pencil which containstalc, operations of selecting talc which does not include asbestos andcontrolling its quality are conducted usually. The reason is that sincetalc is a natural mineral, it sometimes contains asbestos which arepointed out recently that it may have a bad effect on a human bodydepending on its production area where it is mined.

Since operations of quality control are complicated, if possible, it isdesirable to use a body filler which has a stabilized quality and isexcellent in safety in order to make operations easier. It is alsonecessary for a non-calcined lead of a colored pencil using a bodyfiller that does not require such operations to have physical propertiesincluding the equivalent tinting amount (tinting strength), good bendingstrength, good writing performance, and the like.

In other words, conventionally, there have been lying some problems inproviding a non-calcined lead of a colored pencil with good moldabilityand bending strength of a lead as well as improved water resistance evenwhen oily substances that are in liquids at an ordinary temperature aremixed as waxes and/or oils. Needless to say, in the case where waxesand/or oils that are in solids at an ordinary temperature are mixed, thesituation is worse. In addition, there has been lying another problem ofproviding a non-calcined lead of a colored pencil without lowering theproperties as a drawing tool including bending strength, writingperformance, and the like, without the need of confirming the absence ofasbestos, and further, with good safety compared with a non-calcinedlead of a colored pencil which contains conventional talc as a bodyfiller.

DISCLOSURE OF THE INVENTION

In the present invention, a non-calcined lead of a colored pencil whichcontains a colorant, a binder, a body filler, waxes and/or oils, and ahydrophilic surfactant and which contains polyoxyethylene additives ofoils as above hydrophilic surfactant is adopted. In particular, as abovehydrophilic surfactant, polyoxyethylene additives of oils that are atleast either of polyoxyethylene castor oil or polyoxyethylene hardenedcastor oil are preferable. The non-calcined lead of a colored pencil ofthe present invention containing polyoxyethylene additive of oils as ahydrophilic surfactant has good moldability and bending strength of alead when waxes and/or oils are contained, in particular, even when oilysubstances in liquids at an ordinary temperature is contained as waxesand/or oils.

Further, when a non-calcined lead of a colored pencil which contains acolorant, a binder, a body filler, waxes and/or oils, and a hydrophilicsurfactant is so made as to contain a water repellent substance,strength of a lead under high moisture and water resistant property of awritten mark can be improved.

Although the most preferable examples of a non-calcined lead of acolored pencil of the present invention which further contains a waterrepellent substance are not specifically limited, it is the non-calcinedlead of a colored pencil which contains a colorant, a binder, a bodyfiller, waxes and/or oils, and a hydrophilic surfactant and whichcontains a polyoxyethylene additive of oils as above hydrophilicsurfactant and which contains a paraffin wax emulsion of an O/W emulsionwhich does not contain a surfactant as above water repellent substanceis preferable.

In addition, by using plate alumina and/or plate alumina hydrate insteadof using talc as a raw material, a non-calcined lead of a colored pencilwhich contains plate alumina and/or plate alumina hydrate showssatisfactory bending strength like a conventional non-calcined lead of acolored pencil containing talc due to the property of plate aluminaand/or plate alumina hydrate of being oriented in one direction in amolding. In addition, in a non-calcined lead of a colored pencil whichcontains plate alumina and/or plate alumina hydrate, quality controloperations that are some of the processes in producing a non-calcinedlead of a colored pencil are easily conducted since the operations ofconfirming the absence of asbestos in a body filler is not required.Further, a non-calcined lead of a colored pencil which contains platealumina and/or plate alumina hydrate is excellent in safety since thereis no risk of containing asbestos unlike in the case of usingconventional talc.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A non-calcined lead of a colored pencil of the present inventioncontains a colorant, a binder, a body filler, waxes and/or oils, and ahydrophilic surfactant, and a polyoxyethylene additive of oils iscontained as a hydrophilic surfactant.

(Hydrophilic Surfactant)

As hydrophilic surfactants in the present invention, known surfactantsmay be used, however, such surfactants are preferable as not to inhibitcoloring (brightness) of colored pencils. As hydrophilic surfactants,when good moldability and bending strength of a lead are required, apolyoxyethylene additive of oils is preferable. Known hydrophilicsurfactants can be used in combinations of two or more of them. Further,in order to realize better compatibility between a binder contained andwaxes and/or oils in the present invention, above hydrophilicsurfactants can be used with oleophilic surfactants together.

Oils in polyoxyethylene additives of above oils are ester of fatty acidand glycerin, however, as oils cited herein, both oils can be usedregardless of natural or synthetic. Examples of plant based natural oilsinclude cotton seed oil, palm oil, castor oil, olive oil, soybean oil,safflower oil, jojoba oil, sunflower oil, and the like. Examples ofplant based natural oils also include hardened oils of the above.Examples of animal based natural oils include beef tallow, whale oil,fish oil, and the like. Examples of animal based natural oils alsoinclude hardened oils of the above.

However, among polyoxyethylene additives of these oils, polyoxyethylenecastor oil or polyoxyethylene hardened castor oil are preferable.Therefore, as a preferred embodiment of the present invention, it isimportant to prepare a non-calcined lead of a colored pencil whichcontains at least either polyoxyethylene castor oil or polyoxyethylenehardened castor oil. For information, it is most suitable to usepolyoxyethylene castor oil whose number of additional moles of ethyleneoxide chain, or n, is 36 mol (H.L.B. value: 10.0) as polyoxyethylenecastor oil or polyoxyethylene hardened castor oil in order to facilitateuniform mixture of water soluble resin which is a binder contained in anon-calcined lead of a colored pencil and waxes and/or oils.

Polyoxyethylene additives of oils as mentioned above, in particular,polyoxyethylene castor oil or polyoxyethylene hardened castor oil iscontained in 0.1 to 10.0% by weight, and preferably 2.5 to 3.5% byweight with respect to the total amount of the raw material composition(in solids). When the above hydrophilic surfactant is contained in lessthan 0.1% by weight, the content is so little that molding of a lead isdifficult and even when molding is made, bending strength of said leadis low, and practicality deteriorates in the case of a non-calcined leadof a colored pencil containing waxes and/or oils in liquids at anordinary temperature. On the other hand, when the above hydrophilicsurfactant is contained greater than 10.0% by weight, water resistancedeteriorates.

(Binder)

As binders used in the present invention, any known binders can be used.However, binders with strength and rigidity are desirable. Examplesinclude sodium carboxy methylcellulose (CMC sodium), ammonium carboxymethylcellulose (CMC ammonium), methylcellulose, hydroxy ethylcellulose,nitrocellulose, polyvinyl alcohol, Arabic gum, bentonite, and the like,and other known water soluble or water insoluble polymeric compound canbe used regardless of whether they are natural or synthetic. These canbe used alone or in combinations. Preferably, it is desirable to useknown water soluble resins and known clay minerals. In addition, theycan be used as a binder solution by adding solvent like water or thelike. A binder is contained in 2 to 15% by weight with respect to thetotal amount of the raw material composition (in solids), and preferablyis contained in 3 to 10% by weight. When the a binder is containedgreater than 15% by weight with respect to the total amount of the rawmaterial composition (in solids), writing performance lowers, wearing ishard to occur, and practicality lowers. On the other hand, when a binderis contained in less than 2% by weight with respect to the total amountof the raw material composition (in solids), molding of a lead becomesdifficult and strength as a pencil lead is hard to get.

(Waxes and/or Oils)

As waxes and/or oils used in the present invention, known waxes and oilscan be used regardless of whether they are in solids or in liquids in astate at an ordinary temperature so long as they do not inhibit coloring(brightness) by a colorant. Examples include a liquid paraffin, siliconeoil, a paraffin wax, a microcrystalline wax, southall wax, a ketonewax,vaseline, hardened beef tallow, a beeswax, a Japan wax, α-olefinoligomer, whale oil, liquefied lanolin, castor oil, olive oil,epoxydized soybean oil, squalene, and the like. Waxes and/or oils can beused alone or in combinations of two or more of them regardless ofwhether they are synthetic or natural.

In particular, when a non-calcined lead of a colored pencil is soproduced that the written mark can be erased with an eraser, it ispreferable to use waxes and/or oils in liquids at an ordinarytemperature as waxes and/or oils. When oily substances in liquids at anordinary temperature are used as waxes and/or oils, the abovehydrophilic surfactant makes oily substances which are in liquids at anordinary temperature present without inhibiting general force of abinder. As a result, a written mark adhered to a paper surface is formedas an agglomerate in which a colorant particle and a body fillerparticle covered with a binder accompany oily substances which are inliquids at an ordinary temperature, thereby realizing a non-calcinedlead of a colored pencil in which the written mark can be erased with aneraser.

The above waxes and/or oils are mixed in order to provide tintingstrength and coloring (brightness) and the waxes and/or oils arecontained in 1 to 20% by weight with respect to the total amount of theraw material composition (in solids), and preferably, 3 to 10% byweight. When the content of waxes and/or oils is less than 1% by weight,writing performance and tinting strength lower, and when the contentexceeds 20% by weight, strength as a pencil lead becomes hard to obtain.

For information, due to the producing process, in mixing the above waxesand/or oils, they may be mixed as an O/W emulsion. A surfactant preparedas an O/W emulsion is not specifically limited. When the above waxesand/or oils are not prepared as an O/W emulsion, it is preferable thatthe above hydrophilic surfactant and the above waxes and/or oils aremixed beforehand, followed by mixing this mixture.

(Colorant)

A colorant used in the present invention is not specifically used, andboth inorganic pigment and organic pigment which have tinting effect andbeautiful coloring (brightness) and which are usually used can be usedalone or in combinations with two or more of them. In addition tofluorescent pigment, pearlescent pigment, metal powder pigment, scalypigment including glass flake pigment, and the like can be used. Thecontent thereof is 0.1 to 20% by weight with respect to the total amountof the raw material composition (in solids), and preferably 1 to 15% byweight. When the above content exceeds 20% by weight with respect to thetotal amount of the raw material composition (in solids), writingperformance lowers and strength as a pencil lead is hard to obtain. Onthe other hand, when the above content is less than 1% by weight withrespect to the total amount of the raw material composition (in solids),in particular, less than 0.1%by weight,coloring(brightness)is notsatisfactory.

(Water Repellent Substance)

Further, when a non-calcined lead of a colored pencil of the presentinvention is used for the usage requiring water resistance in a writtenmark, it is preferable to further contain water repellent substances. Bycontaining water repellent substances in a non-calcined lead of acolored pencil, moisture resistance (strength of moisture resistance) ofa lead and water resistance of a written mark can be obtained even for anon-calcined lead of a colored pencil with a hydrophilic surfactantcontained.

As the above water repellent substances, known water repellencyimparting agents and the like can be used. As the above water repellentsubstances, substances with water repellent substances dispersed inwater medium are preferable since strength is enhanced due to thepresence of water repellent substances finely in a molded non-calcinedlead of a colored pencil, and from the viewpoint of water resistance, anO/W emulsion which does not contain a surfactant is more preferable, andfurther, in particular, using paraffin wax emulsion is the mostsuitable. For information, when an O/W emulsion which does not containthe above surfactant is mixed as a raw material, since only the abovewater repellent substances which are oily components remain as effectivecomponents after drying in production processes, moisture resistance ofa color pencil lead and water resistance of a written mark can beenhanced.

The content of the above water repellent substance, in particular, anO/W emulsion which does not contain a surfactant, and above all, aparaffin wax emulsion is preferably contained in 0.1 to 5.0% by weightwith respect to the total amount of the raw material composition (insolids) as effective components (water repellent component or waxcomponent), and its optimum range is 1.5 to 4.5% by weight. When thecontent of water repellent substances is less than 0.1% by weight withrespect to the total amount of the raw material composition (in solids),water resistance and moisture resistance lower and when the contentexceeds 5.0% by weight, moldability, bending strength, and erasabilitywith an eraser lower.

(Body Filler)

As a body filler, known body filler can be used, however, a body fillerwhich does not inhibit coloring (brightness) and tinting strength ispreferable. To be specific, talc, kaolin, calcium carbonate, aluminasilicate, white mica, magnesium carbonate, silica, and the like can beexemplified. Then, among them, they can be used optionally selectingeither alone or in combinations of two or more of them. For information,kaolin and white mica are the most suitable for a body filler. A bodyfiller is contained in 60 to 80% by weight with respect to the totalamount of the raw material composition (in solids), and preferablycontained in 65 to 75% by weight. When the content of a body fillerexceeds 80% by weight with respect to the total amount of the rawmaterial composition (in solids), moldability of a lead lowers and whenthe content of a body filler is less than 60% by weight, writingperformance lowers.

(Plate Type Alumina and/or Plate Type Alumina Hydrate)

A non-calcined lead of a colored pencil of the present invention cancontain plate type alumina and/or plate type alumina hydrate as a partof or total of a body filler. By using plate type alumina and/or platetype alumina hydrate as a part of or total of a body filler instead ofusing talc, there occurs no concern of containing asbestos and there isno need for complex quality control operation unlike the case when talcis used. Therefore, a non-calcined lead of a colored pencil of thepresent invention is excellent in safety and in operation. Although theabove plate type alumina and/or plate type alumina hydrate are notspecifically limited, it is enough as far as a non-calcined lead of acolored pencil in which plate type alumina and/or plate type aluminahydrate are contained as a body filler shows the same or better bendingstrength and writing performance.

A non-calcined lead of a colored pencil in which plate type aluminaand/or plate type alumina hydrate are contained as a body fillerdevelops bending strength with plate type alumina and/or plate typealumina hydrate orienting in one direction in molding as in conventionaltalc, and therefore since operation for confirmation of absence ofasbestos in a body filler is not required, quality control operation asa part of a production process of a non-calcined lead of a coloredpencil is easy, and moreover, since there is no possibility ofcontaining asbestos as in conventional talc, a non-calcined lead of acolored pencil with excellent safety can be obtained.

For information, by using plate type alumina and/or plate type aluminahydrate and a safe body filler other than talc together as a body fillerwhich is contained in a non-calcined lead of a colored pencil, anon-calcined lead of a colored pencil of the present invention can beproduced as a non-calcined lead of a colored pencil with safety.

In the above alumina and/or plate type alumina hydrate, particles in thepowder may be either hexagonal plate types or circle plate types as longas they are substantially flat plate types, and those particles in thepowder of alumina and/or plate type alumina hydrate need not haveuniform shapes due to the grinding. The above alumina and/or plate typealumina hydrate are not specifically limited as polymorphism, and theabove plate type alumina may be alone or in combinations of two or moreof them selected from the group of α-Al₂O₃, γ-Al₂O₃, and θ-Al₂O₃ or theymay be alone or in combinations of two or more of them selected from thegroup of α-Al₂O₃ hydrate, γ-Al₂O₃ hydrate, and θ-Al₂O₃ hydrate. However,it is preferable that plate type alumina is α-Al₂O₃ and that plate typealumina hydrate is α-Al₂O₃ hydrate since they have no pores on thesurface, and comparatively large amount of plate type alumina can beused in the mixing of a non-calcined lead of a colored pencil withoutdeteriorating strength and they are easy to disperse. Plate type aluminahydrate used may be plate type mono hydrate, plate type dehydrate, orplate type trihydrate. For information, when either γ-Al₂O₃ or θ-Al₂O₃alone or in combinations thereof are used as a plate type alumina andwhen either γ-Al₂O₃ or θ-Al₂O₃ hydrate alone or in combinations thereofare used as a plate type alumina, they may be used directly. However,when the surface of plate type alumina and/or plate type alumina hydrateare treated with coupling agents including silane coupling agents ortitanate coupling agents, they can preferably be used like α-Al₂O₃.

The production method of the above plate type alumina and/or plate typealumina hydrate is not specifically limited, and, for example, α-Al₂O₃and α-Al₂O₃ hydrate can be obtained by regulating granularity ofaluminum hydroxide obtained by Bayer process, followed by hydrothermalsynthesis process (350° C. and higher, 200 atm and lower)using crystalinhibiting agents including Na₂SiO₃, and the like.

Although the particle diameter of the above plate type alumina and/orplate type alumina hydrate is not specifically limited, those with adiameter of 0.1 to 20 μm can preferably be used. In addition, althoughthe aspect ratio of the above plate type alumina and/or plate typealumina hydrate is not specifically limited, powder of those with a meanvalue of 2 to 50 can preferably be used. Here, the aspect ratio isrepresented by dividing an average diameter of a particle (μm) bythickness (μm). To be specific, Serafu FYA00610, Serafu FYA02025, andSerafu 10030 (manufactured by YKK Corporation) and Therases BMN,Therasis BMN-B (manufactured by Kawai Lime KK) can be used as the abovealumina and/or plate type alumina hydrate. The above alumina and/orplate type alumina hydrate can be used alone or in combinations. Aluminaand/or plate type alumina hydrate are preferably contained in 2 to 85%by weight with respect to the total amount of the raw material of anon-calcined lead of a colored pencil in solids and are more preferablycontained in 5 to 80% by weight. When alumina and/or plate type aluminahydrate are contained in excess of 85% by weight with respect to thetotal amount of the raw material of a non-calcined lead of a coloredpencil in solids, coloring (brightness) lowers and therefore it is notpreferable. On the other hand, when plate type alumina and/or plate typealumina hydrate are contained in less than 2% by weight with respect tothe total amount of the raw material of a non-calcined lead of a coloredpencil in solids, writing performance lowers when written, and tintingstrength lowers, and formation of a lead becomes difficult, therefore itis not preferable.

For information, either of plate type alumina and/or plate type aluminahydrate may consist of one kind or it may consist of various kinds indifferent shapes, particle diameters, compositions or the like, or platetype alumina and plate type alumina hydrate may be a mixture in whichvarious kinds are mixed.

(Other Components)

For information, in producing a non-calcined lead of a colored pencil,as required, other additives including antiseptic mildew proofingagents, lubricants, or the like can be used in addition to solventsincluding water and alcohol and the like for dissolving a water-solubleresin.

(Production Method)

Basically, in the production method of a non-calcined lead of a coloredpencil in the present invention, each component described above aremixed, molded into specific shapes, thereby obtaining a non-calcinedlead of a colored pencil of the present invention. For example, the rawmaterials are kneaded using kneading machines (kneader and the like),thereafter heating to the temperature of 60° C. for 4 hours, evaporatingwater in an appropriate manner. Next, the kneaded materials arepreparatively formed using a pressurizing machine, followed by extrudinginto a molding to produce a pencil lead with a diameter of 3 mm with aplunger type molding machine by, thereafter drying (for 12 hours at thetemperature of 70° C., for example), thereby preparing a non-calcinedlead of a colored pencil of the present invention. A non-calcined leadof a colored pencil of the present invention can be obtained by furtherimpregnating oils and waxes in this molding as required.

EXAMPLES

The present invention will be further detailed by way of the followingexamples and comparative examples thereof, but the present inventionwill not be limited by these examples.

A non-calcined lead of a colored pencil of Examples 1 to 9, ComparativeExamples 1 and 2 was obtained by the following process using the rawmaterials and contents thereof shown in the Table 1. First, a colorant,a body filler, and a binder were kneaded with substantially the sameamount of the solvent for about 8 hours at the temperature of 60° C.Subsequently, a mixture of a hydrophilic surfactant and waxes and/oroils that are oily substances were added thereto and further, asrequired, a water repellent substances were added. Next, after lettingthis through three rolls once without heating, thereafter degassing, itwas molded preparatively with a plunger type molding machine, followedby extruding into a molding to produce a pencil lead with a diameter of3 mm, thereafter drying for at least 12 hours at the temperature of 70°C., thereby preparing a non-calcined lead of a colored pencil of thepresent invention.

For information, the content of each raw material in Table 1 isrepresented by % by weight as in solids and water was used as a solvent.

TABLE 1 [% by weight] Comparative Example Example 1 2 3 4 5 6 7 8 9 1 2Raw material composition Binder (a) 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.08.0 8.0 Body filler (a) 67.0 67.0 67.0 67.0 67.0 69.5 59.5 58.0 60.572.5 70.0 Colorant (a) 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.015.0 Waxes and/or oils 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5Hydrophilic surfactant (a) 3.0 3.0 3.0 3.0 12.0 12.0 (b) 3.0 (c) 1.0 (d)2.7 Oleophilic surfactant 2.0 0.3 Water repellent substance (as wax) (a)2.5 2.5 2.5 2.5 10.0 2.5 2.5 (b) 2.5 Total 100 100 100 100 100 100 100100 100 100 100 Physical properties Bending strength Value (MPa) 21.520.3 19.1 18.5 19.7 23.8 15.8 13.5 14.9 9.4 — Evaluation ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯◯ X — Moldability ⊚ ⊚ ◯ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ X X Bending strength after 20.2 19.418.6 18.4 18.3 9.7 15.4 5.1 — — — preservation with 80% moisture (MPa)Tinting strength Value (m/25 m) 23.4 24.3 26.6 26.8 25.8 19.6 32.8 35.429.6 — — Evaluation ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ — — Erasibility ⊚ ⊚ ⊚ ⊚ ⊚ ◯ X ◯ ◯X X

A non-calcined lead of a colored pencil of Examples 10 to 13,Comparative Examples 3 to 6 was obtained by the following process usingthe raw materials and contents thereof shown in the Table 2. First,plate type alumina, plate type alumina hydrate, a colorant, and a binderwere kneaded using a kneader with substantially the same amount of thesolvent for about 4 hours at the temperature of 60° C., followed byadding and kneading a mixture of a hydrophilic surfactant and waxesand/or oils that are oily substances prepared in advance, further addinga water repellent substances thereafter kneading.

For information, the content of each raw material in Table 2 isrepresented by % by weight as in solids and water was used as a solvent.

TABLE 2 [% by weight] Example Comparative Example 10 11 12 13 3 4 5 6Raw material composition Binder (b) 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0Plate type 35.1 70.1 14.0 4.2 alumina Plate type 56.1 alumina hy- drateBody filler (a) 70.1 70.1 Plate filler (b) 35.1 14.0 56.1 70.1 70.1Lubricant (a) 4.2 4.2 4.2 4.2 4.2 4.2 Lubricant (b) 4.2 Colorant (b) 6.76.7 6.7 6.7 6.7 6.7 6.7 6.7 Oils and/or 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5waxes Hydrophilic 2.9 2.9 2.9 2.9 2.9 2.9 2.9 2.9 surfactants (c) Waterrepellent 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 substance (c) Total 100.0100.0 100.0 100.0 100.0 100.0 100.0 100.0 Physical properties Bendingstrength Value (MPa) 30.5 28.0 23.2 32.8 39.6 20.0 12.8 20.5 Evaluation◯ ◯ ◯ ⊚ ⊚ ◯ X ◯ Moldability ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ Bending 28.7 26.3 21.9 30.837.2 18.8 14.9 19.3 strength af- ter preserva- tion with 80% moisture(MPa) Writing perfor- ◯ ⊚ ⊚ ◯ X ⊚ ⊚ Δ mance Tinting strength Value(mg/25 13.0 15.3 18.2 10.0 4.1 16.8 17.0 13.8 m) Evaluation ◯ ◯ ◯ Δ X ◯◯ ◯ Erasability ◯ ⊚ ⊚ ◯ Δ ⊚ ⊚ ⊚

For information, in Tables 1 and 2, each component is as follows.

Binder

-   -   (a): Hydroxyethyl cellulose (trade name “Tylose H 20P2”,        manufactured by Clariant Polymers KK)    -   (b): Polyvinyl alcohol (trade name “KURARAY Poval”, manufactured        by KURARAY CO., LTD)

Body Filler

-   -   (a): Pigment White 26 (trade name “MICRO ACE P-4”, manufactured        by NIPPON TALC CO., LTD)    -   (b): Kaolin (trade name “KAOBRIGHT”, manufactured by TSUCHIYA        KAOLIN KK)

Colorant

-   -   (a): Watching Red Sr (trade name “Red SR-200PH”, manufactured by        NOMA KAGAKUKOGYO KK)    -   (b): Phthalo cyanine blue (tradename “HOSTAPERM BLUE B2G”,        manufactured by Clariant Japan) and titanium oxide (trade name        “Tipure R 900”, manufactured by Dupont KK)

Waxes and/or oils: liquid paraffin (trade name “ONDINA OIL”,manufactured by Showa Shell Sekiyu KK)

Hydrophilic Surfactant

-   -   (a): Polyoxyethylene castor oil (trade name “Emulsogen EL”,        manufactured by Clariant Japan, number of additional moles of        ethylene oxide chain: n=36 mol)    -   (b): Polyoxyethylene hardened castor oil (trade name “HCO-20”,        manufactured by Nikko Chemicals Co.,Ltd, number of additional        moles of ethylene oxide chain: n=20 mol)    -   (c): Monooleic acid polyoxyethylene sorbitan(trade name “TO-10”,        manufactured by Nikko Chemicals Co.,Ltd, number of additional        moles of ethylene oxide chain: n=20 mol)    -   (d): Monooleic acid decaglyceryl (tradename“Decaglyn 1-O”,        manufactured by Nikko Chemicals Co.,Ltd)

Oleophilic surfactant: Sesqui oleic acid sorbitan (trade name “SO-15”,manufactured by Nikko Chemicals Co.,Ltd)

Water Repellent Substances

-   -   (a): Paraffin wax emulsion (trade name “Pekophob 1160”,        manufactured by Dick Peters BV Co., Ltd)    -   (b): Paraffin wax emulsion(trade name “E701K”, manufactured by        Clariant Japan Co., Ltd)    -   (c): Paraffin wax emulsion(trade name “Pekophob”, manufactured        by Dick Peters BV Co., Ltd)

Lubricant

-   -   (a): Boron nitride    -   (b): Mica (trade name “MICA POWDER A-11”, manufactured by        Yamaguchi Unmo Kogyosho KK)

(Evaluation)

Erasability with an eraser, bending strength (Mpa) after preservationwith 80% moisture, tinting amount (mg/25 m), and moldability wereevaluated respectively on a non-calcined lead of a colored pencil in theExamples and Comparative Examples shown in Table 1.

(Bending Strength)

Bending strength was evaluated based on the JIS-S-6005. That is, a loadis applied to a central part of a colored pencil lead supported betweenboth of the supporting points and the load was measured at the time of alead breakage, substituting the formula specified by JIS examinationmethod. The result figure was evaluated based on the following criteria;⊚ as having higher bending strength than a conventional non-calcinedlead of a colored pencil, ◯ as having substantially the same bendingstrength as conventional a non-calcined lead of a colored pencil, X ashaving lower bending strength than a conventional non-calcined lead of acolored pencil and cannot be used.

(Bending Strength After Preservation with 80% Moisture)

This bending strength after preservation with 80% moisture was measuredand evaluated as in the above bending strength test after preservation 6hours under the 80% moisture.

(Tinting Strength)

A tinting strength amount was obtained by calculating the differencebetween the weight of a lead after written 25 m and that of a leadbefore written. The result figure was evaluated based on the followingcriteria; ◯ as having more superior tinting strength amount to aconventionally used non-calcined lead of a colored pencil, Δ as havingsubstantially the same tinting strength amount as a conventionally usednon-calcined lead of a colored pencil, X as having inferior tintingstrength amount to a conventionally used non-calcined lead of a coloredpencil.

(Moldability)

The result was shown based on the criteria of X as not less than 40% ofthe molded leads were broken to pieces, Δ as less than 40% and not lessthan 35% of leads were broken, ◯ as less than 35% and not less than 30%of leads were broken, and ⊚ as less than 35% of leads were broken duringthe time of molding or drying.

(Erasability with an Eraser)

The erasability with an eraser was evaluated by writing on the drawingpaper using each of colored pencils prepared in Examples and ComparativeExamples. The eraser used in this test was that available from RabbitCo., LTD. under the trade name of “RC-60”. The erasability with aneraser was evaluated on the following criteria; ⊚: The erasability withan eraser was excellent,◯: The erasability with an eraser was good, Δ:The erasability with an eraser was not very good, and X: the erasabilitywith an eraser was not good.

(Writing Performance)

Sensory evaluation was conducted on writing performance using a coloredpencil lead whose Example and Comparative Example numbers wereconcealed. To be specific, colored pencils using non-calcined leads ofcolored pencils in Examples and Comparative Examples were produced andthe evaluation based on the sensory feeling of 10 monitors when theywrote on a drawing paper under the condition of the temperature of 20°C. and both with 65% and 85% moisture. The result was shown based on thecriteria; ⊚ as 10 out of 10 monitors judged the writing performance wasgood, ◯ as 8 to 9 out of 10 monitors judged the writing performance wasgood, Δ as not more than 7 and not less than 5 out of 10 monitors judgedthe writing performance was good,and X as not more than 4 out of 10monitors judged the writing performance was good.

From Table 1, non-calcined leads of colored pencils of Examples 1, 2,and 5 to 9 using non-calcined leads of colored pencils which containpolyoxyethylene additives of oils as surfactants had better bendingstrength and moldability with more than just usable compared withnon-calcined leads of colored pencils of Comparative Examples 1 and 2which do not contain hydrophilic surfactants. In addition, compared withnon-calcined leads of colored pencils of Examples 3 and 4 which containsorbitan fatty acid ester surfactants, non-calcined leads of coloredpencils of Examples 1, 2 and 6 had improved bending strength andmoldability of a lead, and non-calcined leads of colored pencils ofExamples 5 and 7 had improved only moldability depending on the kindsand content of water repellent substances, and further, non-calcinedleads of colored pencils of Examples 8 and 9 had improved onlymoldability due to the fact that they contained a large amount ofhydrophilic surfactant.

Non-calcined leads of colored pencils of Examples 1 to 5 which containwater repellent substances together with hydrophilic surfactant,maintained the ordinary bending strength in a preferable manner, whilepreventing the lowering in bending strength after preservation with 80%moisture, and further, erasability with an eraser, tinting strength, andmoldability are preferable, thereby capable of obtaining the wellbalanced properties as non-calcined leads of colored pencils erasablewith an eraser. On the other hand, since a non-calcined lead of acolored pencil of Example 6 contains hydrophilic surfactants and doesnot contain water repellent substances, it was judged that moistureresistant property of a lead and that of a written mark lowered sincebending strength after preservation with 80% moisture lowered althoughbending strength improved.

For information, although a non-calcined lead of a colored pencil inExample 8 is a non-calcined lead of a colored pencil which containspolyoxyethylene additives of oils as hydrophilic surfactants, since ahydrophilic surfactant is contained more than 10.0% by weight withrespect to the total amount of the raw material composition in solids,hydrophilic property is too strong that water resistant property lowers,however, compared to a non-calcined lead of a colored pencil in Example9, water resistant property improves to the level where tests areapplicable to bending strength after the preservation with 80% moisture.

Further, although it isn't shown in Table 1, in a non-calcined lead of acolored pencil in which polyoxyethylene additives of oils are containedin less than 0.1% by weight with respect to the total amount of the rawmaterial composition in solids, since the content is so little that theobtained result was not so different from a non-calcined lead of acolored pencil in Comparative Example 1 and in the case of anon-calcined lead of a colored pencil which contains oily substances inliquids at an ordinary temperature, moldability of a lead becomesdifficult and even when it is molded, bending strength of the said leadis low and the usability lowered.

Further, even in the case of a non-calcined lead of a colored pencil inwhich O/W emulsion which does not contain a surfactant, in particular,in which a paraffin wax emulsion is mixed, in Comparative Example 4 inwhich the effective component (water repellent component or waxcomponent) was mixed greater than 5.0% by weight with respect to thetotal amount of the raw material composition in solids, moldability of alead becomes difficult and even when it is molded, bending strength anderasability with an eraser lowers.

On the other hand, when a water repellent substance is contained in lessthan 0.1% by weight with respect to the total amount of the raw materialcomposition in solids, water resistant property and moisture resistantproperty lowered. For information, in Comparative Example 2, in whichonly a water repellent substances were mixed without mixing hydrophilicsubstances, molding of a lead was impossible and preparing coloredpencils itself was difficult. For information, “-” in the propertycolumn of Table 1 shows that the measurement of numerical values orevaluation thereof was not available.

A non-calcined lead of a colored pencil in Examples 10 to 13 had thesame or better bending strength compared to a non-calcined lead of acolored pencil using talc (Comparative Examples 4 to 6) and erasabilitywith an eraser were also good. In particular, a non-calcined lead of acolored pencil in Examples 10 to 13 had good tinting strength as well asbending strength, writing performance, moldability and erasability.

INDUSTRIAL APPLICABILITY

As mentioned above, since the present invention relates to anon-calcined lead of a colored pencil which contains a colorant, abinder, a body filler, waxes and/or oils, and a hydrophilic surfactant,and contains a polyoxyethylene additive of oils as the above hydrophilicsurfactant, moldability and bending strength of a lead are good evenwhen oily substances which are in liquids at an ordinary temperature arecontained as waxes and/or oils. In addition, in the case of anon-calcined lead of a colored pencil which also contains waterrepellent substances in addition to a colorant, a binder, a body filler,waxes and/or oils, and a hydrophilic surfactant, moisture resistance ofa lead and water resistance of a written mark can be improved.

Further, since the present invention relates to a non-calcined lead of acolored pencil which contains plate type alumina and/or a plate typealumina hydrate, it does not contain asbestos, therefore, it isexcellent in safety. In addition, when compared with a non-calcined leadof a colored pencil which contains conventional talc as a body filler, anon-calcined lead of a colored pencil which contains plate type aluminaand/or a plate type alumina hydrate has equivalent tinting amount(tinting strength) and bending strength, yet lowering of physicalproperty is not observed with good writing performance. Therefore, anon-calcined lead of a colored pencil with excellence in safety andusability can be provided.

1. A non-calcined lead of a colored pencil comprising a colorant, a binder, a body filler, waxes and/or oils, and a hydrophilic surfactant, wherein a polyoxyethylene additive of oils composed of fatty acid ester and glycerine ester is contained as said hydrophilic surfactant.
 2. A non-calcined lead of a colored pencil as a set forth in claim 1, wherein the waxes and/or oils are oily substances in liquids at an ordinary temperature.
 3. A non-calcined lead of a colored pencil as set forth in claim 1, wherein the polyoxyethylene additive of oils contains at least either of polyoxyethylene castor oil or polyoxyethylene hardened caster oil.
 4. A non-calcined lead of a colored pencil as set forth in claim 1, wherein the polyoxyethlene additive of oils is contained in 0.1 to 10.0% by weight with respect to the total amount of the raw material composition in solids.
 5. A non-calcined lead of a colored pencil comprising a colorant, a binder, a body filler, waxes and/or oils, and a hydrophilic surfactant, further comprising a water repellent substance.
 6. A non-calcined lead of a colored pencil as set further in claim 5, wherein the water repellent substance is a water repellency imparting agent with a water repellent substance dispersed in water medium.
 7. A non-calcined lead of a colored pencil as set further in claim 5, wherein the water repellent substance is an O/W emulsion which dos not contain a surfactant.
 8. A non-calcined lead of a colored pencil as set forth in claim 7, wherein the O/W emulsion which does not contain surfactant is a paraffin wax emulsion.
 9. A non-calcined lead of a colored pencil as set forth in claim 5, wherein the water repellent substance is contained in 0.1 to 5.0% by weight with respect to the total amount of the raw material composition in solids.
 10. A non-calcined lead of a colored pencil as set further in claim 5, wherein the hydrophilic surfactant comprises polyoxyethylene additive of oils in an amount of 0.1 to 10.0% by weight with respect to the total amount of the raw material composition in solids.
 11. A non-calcined lead of a colored pencil comprising a plate alumina and/or a plate alumina hydrate as a body filler.
 12. A non-calcined lead of a colored pencil as set forth in claim 11, wherein said plate alumina is selected at least one species from the group consisting of α-Al₂O₃, γ-Al₂O₃, θ-Al₂O₃, and said plate alumina hydrate is selected at least one species from the group consisting of α-Al₂O₃ hydrate, γ-Al₂O₃ hydrate, and θ-Al₂O₃ hydrate.
 13. A non-calcined lead of a colored pencil as set forth in claim 11, wherein the plate alumina and/or a plate alumina hydrate are/is contained in 2 to 85% by weight with respect to the total amount of the non-calcined lead of a colored pencil. 